Nitrous and bolt ons?

super red91

Registered User
Im considering getting a nitrous kit for my car. My car is a 91 5spd with 70k on it now. It has all of the bolt ons except underdrive pulleys. I have my entire exhaust done dual 2.5'' into 3'' and then back into dual 2.5''. I had It dynoed with a leaking double ic and made 260rwhp and 345ft lbs, since then i have added a fmic and lightweight jackshaft pulley. I ran a 14.3@97.9mph at the track with street tires and bad wheelhop with this setup. I wanted to know if i would be safe to run nitrous on my car? What size shot? and what kit should I get? Also how much of a drop in et would i see from the nitrous? I did already did a search and read alot about nitrous on sc's, i just wanted to get a more specific reply for my car. Thanks
 
i run it now and am very happy with it. On the dyno i got 70hp from a 65 dry shot. I was running a 14.211 with very little, just an exhaust with no cats, an intake, and a 5% pulley and IC fan. I had no other bolt ons at that time and was running street tires. Now the car comes alive so much more, but i cant seem to hook up at the track. This summer i got new gears, suspension, fuel mods, etc. etc......and also got some drag radials, but havent been able to get to the track again. I hope to soon...but I would say that you are plenty safe using the bottle. Put it on the dyno so that you know you're not running lean when you use it. Just get a wideband run and you'll know for sure.
 
What is the kit # that you bought for your car? Alos where did u get it from and do you know where the cheapest place to get it at? Does anyone else with nitrous experience have any say? Thanks
 
mines zex #82011 and i got it from summit (part number there is CCA-82011) i think it was somthing like $517.90 shipped. i haven't used it much, but from the times i did i liked it a lot. Haven't used it lately becuase i need bigger injectors :(
 
05115NOS is the kit if you want to go with the Holley/NOS (blue NOS bottle) brand. You can order it from Jegs for about $479.95 and I think they ship it free. Its a dry kit (just sprays N20 into your intake tract) and is adjustable from 50-125hp and comes with a 10 lb. bottle.
 
Whats the differnce between the NOS kit and the Zex kit? Also what size shot do you have on your cars and what have u run with them? What size do u think i should go with and what should i expect to run? I saw wayne ing ran a 13.0 with nitrous in his one car and a 13.3 in his other car, do you happen to know what other mods he had done to his car when he ran that and what size shot he was using? Thanks for all the help so far
 
well the nos kit is just a dry kit...and there is no adjustment for fuel. You either have to run rich, or retard the timing when you are using it. This gets kind of hard on cars like ours. The best would be a wet kit. This way you dont have to do anything...the fuel is mixed in the nozzle and supplied automatically when you spray. The Zex kit is a dry kit, however they use a different method. It has a management unit that the nitrous is delivered from...all the solenoids are in that box. When the nitrous it armed....it can only be activated at WOT....it takes a voltage reading off the TPS, and will only activate past 4.2 volts.....or WOT. Other kits must use a micro switch, and you have to make brackets etc... This kit has one single wire to get that reading. Also, when the nitrous is being used...it takes a reading of bottle pressure and uses a small amount of that nitrous pressure to push harder on the fuel regulator. Under normal driving...as less vacumm is going through a motor..the higher the fuel pressure gets. Our reg. is set at 39.5psi static...at 0psi boost. At boost...1psi is about 1psi of increased fuel pressure. So at wot we have about 54psi. The zex kit will push even harder on the diaphram in the regulator making the pressure around 60psi. The increased pressure provides the added fuel for the nitrous. The kit is still a dry kit, but automatically addes more fuel for you. I had my doubts about the kit but it does indeed work. While on the dyno....when the kit was armed it read about 50psi fuel pressure. ONce the nitrous was in use the fuel pressure instantly went up to past 60psi. This proves that it works. Also...i was afraid it wasn't working so at the dyno it used the 65hp nitrous jet and the 75hp fuel jet for safety. My a/f ratio was very very rich at 9.54 : 1. I changed the jets and then it evened out to about 11.5 :1. I have a good a/f ratio...and an easy 70hp with the 65hp jets. I got mine from a local speed shop....and it was 490 brand new...next day arrival. I got a good deal, but the going rate its around 550. I also had to get a purge kit for the track which ran another 70...and also got a bottle pressure guage for more consitancy. I used the same kit # as Guss. Its for honda's or any other imports. Zex only has two kit numbers.....55-75hp for imports and 75-125 for stangs and camaros. I got the smaller kit, but the only difference is whats jets are included in the kit. SO i could jet different jets and still achieve 125hp..but thats a lot on our motors. I wouldn't go past 75hp. Any more question just ask,....i hope i answered your question.
 
Hey fastsc92 thanks for all the info. I think im gonna go with the zex kit because of how easy it is to install and its a little cheaper than the other kits. Like I said before does anyone know what wayne ing had done to his car to get them to run in the low 13's. Also what do u think i would run with a 55 or 65 shot.
 
its really all in how you race. My car can run 14 flats all day, but i cant hook up, and i get 2.3 60' times. If it hooks up with my et streets( havent tried them yet) then i should get a 1.8 60'. Rule of thumb is every tenth off the 60' is 2 tenths in the end. So i should bring my time to about a 13 flat. It pulls really hard, just need to get that power to the ground. Your time depends on a lot of things too. You need to have the proper fuel delivery. I would at least get 38lb injectos and a maf...as well as a high flow fuel pump. Dont forget about a good exhaust if you havent gotten one. Also with my car being a 5 speed...it gets a lot of wheel hop and you have to learn how to launch it and slip the clutch. I got it down pat so that i get a R/T of .597 and lower and no hop...just spinning. When the nitrous kicks on in 2nd gear i cant keep it from going sideways. I'd say that you can get around a mid 13 ...somewhere around a 13.6- 13.3. Just a guess though. You have the mods to get there. I really dont have any mods to the motor. I have the stock blower and top...as well at the IC and tubing. All stock heads..etc... so i'm pretty close, but i think you'll have me beat.
 
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Well i already have 42lb injectors and a 255lph fuel pump and a C&L 76mm maf with the right sampling tube so i should have enough fuel. Everyhting on my exhaust is also done too.
 
Everone's motors are different, but i'd say you are safe to use it. Rule of thumb that i found was that a 60hp shot of nitrous takes about .8 -1.0 off your 1/4 mile time. Seems to work out about right from what i've seen on my buddies cars.
 
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